Individuals and large companies spend large amounts of time and money to advertise or market their goods and/or services. The media for advertising vary widely, from old fashioned word-of-mouth, for example, to newspaper and magazine ads, billboards, promotional events and sponsorship thereof, radio and television ads, and more recently ads posted in the on-line world such as on personal web sites or through public on-line billboards. The costs of the various forms of advertising vary greatly, as do their success rates, depending on many factors including demographics of the targeted audience, time, place, and duration of the ads, and many other unknown factors. Since society and the economy are always changing, the marketing/advertising industry is always looking for new ways to reach large amounts of potential customers for relatively little cost.